Mycoplasmas of goats and sheep

Polymerase chain reaction and restriction endonuclease digestion for selected members of the "Mycoplasma mycoides cluster" and Mycoplasma putrefaciens

A specific diagnostic method using the polymerase chain reaction, together with restriction endonuclease digestion patterns, was developed for members of the "Mycoplasma mycoides cluster" that normally occur in the United States (i.e., Mycoplasma mycoides subsp. mycoides Large Colony and Mycoplasma capricolum subsp. capricolum in addition to "cluster" mycoplasma, bovine serogroup 7, and Mycoplasma putrefaciens. The digestion of "cluster" polymerase chain reaction DNA (1,225 bp) amplification products with restriction enzymes AseI and SspI gave mycoplasma species-specific patterns for all strains of M. mycoides subsp. mycoides Large Colony, M. capricolum subsp. capricolum, and bovine group 7 tested. Moreover, we found a nonspecific amplification product for M. putrefaciens that occurred with the oligonucleotide primers used for the "M. mycoides cluster" reaction. However, the restriction endonuclease digestion patterns observed with the restriction enzymes AluI, AseI, and SspI for M. putrefaciens were different than the digestion patterns obtained for the other "cluster" mycoplasmas. This report confirms the usefulness of polymerase chain reaction DNA amplification allied with restriction enzyme digestion profile analysis for the rapid and specific identification of mycoplasmas belonging to the "M. mycoides cluster" and M. putrefaciens.

Variable expression and geographic distribution of Mycoplasma agalactiae surface epitopes demonstrated with monoclonal antibodies

Species-specific monoclonal antibodies (MAbs) were developed against Mycoplasma agalactiae reference strain PG2 and French isolate P89 to study the in vitro expression of surface epitopes and to probe the antigenic profiles of 245 field isolates originating from 10 different countries. Colony immunostaining with MAbs on clonal lineage showed that 4 out of 9 species-specific epitopes exhibited a high rate of variation, demonstrating that M. agalactiae possesses a capacity for phenotypic diversification of its surface antigenicity. The emphasis was on dot immunobinding screening of the field isolates with MAbs recognizing permanently expressed epitopes. Eight different profiles could be defined. Great differences in epitope conservation were demonstrated with some area-specific strains completely lacking certain specific determinants. These results indicate that the antigenic variability of M. agalactiae relies not only upon surface switching mechanisms but also upon true epitope differences, partially related to the geographic origin of the isolates.

An immunohistochemical method of detecting Mycoplasma species antigens by use of monoclonal antibodies on paraffin sections of pneumonic bovine and caprine lungs

Lung samples from pneumonic lesions in cattle and goats, naturally or experimentally infected with strains of the Mycoplasma mycoides cluster, were fixed in formalin and embedded in paraffin. An immunohistochemical technique using monoclonal or polyclonal antibodies was performed on tissue sections in order to detect Mycoplasma antigens. Four monoclonal antibodies (MAbs), one (2A3) raised against M. mycoides ssp. mycoides small colony (SC) and large colony (LC), two (1D3 and 5E5) against M. mycoides ssp. capri, and one (5A10) against M. bovis, were used. A range of polyclonal antibodies, raised to the individual subspecies of the M. mycoides cluster, and one to Pasteurella haemolytica, was also used. The MAb 2A3 showed positive immunostaining in lung sections from cattle and goats naturally and experimentally infected with M. mycoides ssp. mycoides SC and LC, but not with pneumonic lesions of cattle and goats due to other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 1D3 showed immunostaining in lung sections from goats naturally and experimentally infected with M. mycoides ssp. capri, but again not with pneumonic lesions caused by other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 5E5 immunoreacted in sections from pneumonic lesions from all animals infected with one of the three M. mycoides cluster subspecies used in the study, but not with M. bovis or Pasteurella infected tissue. Immunoreaction was mainly found in the cell debris around necrotic areas, as well as in macrophages, neutrophils and epithelial cells. The localization of antigens of the M. mycoides cluster using polyclonal antisera followed basically the same pattern as that obtained with the monoclonals. However, a wide cross reactivity was found between different antisera and relatively high background immunostaining was also seen, especially in necrotic areas. The results suggest that immunohistochemical methods using monoclonal antibodies are useful tools for the diagnosis and study of the pathogenesis of pneumonia caused by the Mycoplasmas of the M. mycoides cluster.

Immunohistochemical and ultrastructural characteristics of subsp. in caprine abortion: A case report

Described in this study are the immunohistochemical and ultrastructural findings in a case of caprine abortion due to the experimental infection of the dam with strain GM13 of Mycoplasma capricolum subsp. capricolum. Mycoplasma antigens were seen mainly in choriallantoic trophoblasts and in the lumen of blood vessels in the allantoic membrane. Examination with an electron microscope showed that the chorioallantoic trophoblasts were filled with typical mycoplasma organisms. No other bacteria were observed in any of the samples. Our results confirm by immunohistochemical and electron microscopic techniques that Mycoplasma capricolum subsp. capricolum can cause caprine abortion and that the process can occur without premonitory signs.

Phylogeny of the Mycoplasma mycoides cluster as determined by sequence analysis of the 16S rRNA genes from the two rRNA operons

The so-called Mycoplasma mycoides cluster consists of six species or subspecies of mycoplasmas (Mollicutes). These species are pathogenic for ruminants and some of them are of great concern in veterinary medicine. The members of the M. mycoides cluster have two rRNA operons (rrnA and rrnB). The nucleotide sequences of the 16S rRNA genes of 10 strains, representing all of the known species and subspecies of the M. mycoides cluster, were determined by direct automated solid-phase DNA sequencing. The sequences of both rRNA operons were determined by a novel strategy involving in vitro amplification by PCR with one operon-specific primer pair and one general primer pair. Interestingly, sequence differences (polymorphisms) between the two operons were observed for all strains. Two strains of M. capricolum subsp. capripneumoniae were sequenced, and 15 polymorphisms were found in the type strain (F38) and 17 polymorphisms were found in the other strain (4/2LC). Eight polymorphisms were found in the 16S rRNA genes of the M. mycoides subsp. mycoides small-colony type, and sequence length variations in a poly(A) region were observed in the 16S rRNA genes of the two operons of this species. Secondary-structure analysis showed that polymorphisms were present in both stem and loop regions. The nucleotide substitutions in the polymorphic sites of the stem regions often resulted in a change from a canonical to a noncanonical base pairing or vice versa. A compensatory mutation was never observed in the other nucleotide of the base pair. Phylogenetic analysis based on the 16S rRNA sequences indicated that Mycoplasma sp. strain PG50 should be included in the M. capricolum species group. Furthermore, the 16S rRNA sequences of M. mycoides subsp. capri and the M. mycoides subsp. mycoides large-colony type were 99.9% identical. We therefore suggest that these species be reclassified in a common species group (for instance, "Mycoplasma capri") distinct from the M. mycoides subsp. mycoides small-colony type, which formed an intermediate branch between the M. capricolum species group and the M. capri species group.

Detection of Mycoplasma mycoides subspecies mycoides by monoclonal antibody-based sandwich ELISA

Monoclonal antibodies (MAbs) were produced from a mouse immunised with Mycoplasma mycoides subsp. mycoides small colony (MmmSC) antigen and their use to detect and differentiate strains within the Mycoplasma mycoides cluster investigated in an antigen capture ELISA format. The MAbs produced could not distinguish between MmmSC and M. mycoides subsp. mycoides large colony (MmmLC) strains. However, the sandwich ELISAs developed were able to specifically distinguish these two biotypes from the other four members of the M. mycoides cluster, and from all other mycoplasma or bacteria species examined. The most sensitive application of the test was a combination of enrichment and capture by overnight or 48-h incubations of samples inoculated into mycoplasma broth in antibody-coated microtiter wells.

A pathological and immunohistochemical study of caprine pleuropneumonia induced by subspecies of Mycoplasma mycoides

In a population of 700 goats, 150 died; of these, 29 were necropsied. Ten of the 29 goats had pleuropneumonia. Mycoplasma mycoides subsp. mycoides (Large Colony) (MmmLC), Mycoplasma mycoides subsp. capri (Mmc), and Pasteurella multocida were isolated from five of the pleuropneumonic goats. Gross and microscopical lesions were typical of caprine pleuropneumonia (CPP), with bronchopneumonia, fibrinopurulent or fibrinonecrotic pleuropneumonia and dilatation of the interlobular septa and pleura. Immunohistochemical examination with antisera against MmmLC and Mmc showed mycoplasma antigens in all 10 goats with CPP. In all cases, both MmmLC and Mmc antigens were detected together. Mycoplasma antigens were present in the lumina of the airways and alveoli, mainly inside the cytoplasm of neutrophils and macrophages, but extracellular antigen was demonstrated in areas of necrosis. Pasteurella antigens were detected in four of the 10 animals with CPP. From the histological, immunohistochemical and microbiological results it was concluded that the two mycoplasmas, acting together, caused the pleuropneumonia, with P. multocida playing a subsidiary synergistic role.

Diagnosis of contagious caprine pleuropneumonia by detection and identification of Mycoplasma capricolum subsp. capripneumoniae by PCR and restriction enzyme analysis

Contagious caprine pleuropneumonia (CCPP), one of the most serious and dramatic diseases of goats, is caused by Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae). This organism is very difficult to isolate and to correctly identify. In a previous report we described a method for the rapid detection and identification of M. capripneumoniae. This method is based on a PCR system by which a segment of the 16S rRNA gene from all mycoplasmas of the M. mycoides cluster can be amplified. The PCR product is then analyzed by restriction enzyme cleavage for the identification of M. capripneumoniae DNA. This system has now been further evaluated with respect to specificity and diagnostic efficacy for the identification and direct detection of the organism in clinical material. Identification by restriction enzyme analysis of amplified DNA from mycoplasmas of the M. mycoides cluster was verified for 55 strains, among which were 15 strains of M. capripneumoniae. The PCR was applied to clinical samples from the nose, ear, pharynx, pleural fluid, and lung tissue containing M. capripneumoniae or other mycoplasmas. As expected, mycoplasmas belonging to the M. mycoides cluster could be detected by the PCR. Restriction enzyme analysis of the PCR products could then be applied for the identification of M. capripneumoniae. Clinical samples and cultures containing M. capripneumoniae were dried on filter paper, to try an easier sample transport method, and were tested by PCR. M. capripneumoniae DNA could be detected in the dried specimens, but the sensitivity of the PCR test was reduced.

High mortality in goats associated with the isolation of a strain of Mycoplasma mycoides subsp. mycoides (Large Colony type)

A goat pleuropneumonia outbreak occurring in a herd of 800 animals in the province of Ciudad Real, Spain, is described in this paper. Severe respiratory signs and high mortality were the most significant clinical observations. The adult goats presented mainly respiratory symptoms and/or mastitis, whereas the young animals died showing arthritis and/or keratoconjunctivitis. The most significant lesions were found in the thoracic cavity. A focal extensive fibrinonecrotic pleuropneumonia was macroscopically seen, and the histopathological analysis confirmed a fibrinopurulent and necrotic pleuropneumonia with areas of acute pyogenic bronchopneumonia and fibrinous pericarditis associated with a multifocal purulent mastitis and/or a fibrinopurulent arthritis in some goats. Microbiologically, the mycoplasmas isolated grew rapidly (18-24 h), and, after 48 h, there were colonies of 1-1.5 mm diameter. These isolations were biochemically characterized as Mycoplasma mycoides spp. and showed serological characteristics corresponding to Mycoplasma mycoides subsp. mycoides Large Colony. One of the isolations, the strain 2/93, experimentally showed its pathogenicity causing acute interstitial pneumonia and arthritis when it was inoculated in 1-week-old kids.

Isolation of (LC variant), from two naturally aborted caprine fetuses

Described in this study are 2 cases of caprine abortion associated with the LC type of Mycoplasma mycoides , subsp. mycoides . This mycoplasma and Mycoplasma mycoides , subsp. capri had been previously reported in adult goats in this herd. The abortion took place in the latter part of gestation. Samples from heart blood, lung and pleural exudate were collected for the isolation of mycoplasmas and other bacterials in both fetuses. Two strains of Mycoplasma mycoides , subsp. mycoides (LC variant) were isolated. The only gross lesion of the internal organs in the aborted fetuses was congestion of the lungs. Microscopic lesions were encountered in the lungs, and these were characterized by patchy to diffuse pneumonia. Exfoliated cells, many alveolar macrophages, scattered neutrophils and lymphocytes were seen in the lumen of the terminal airways and alveolar spaces. This report appears to be the first isolation of Mycoplasma mycoides , subsp. mycoides (LC variant) from aborted caprine fetuses.

In vitro amplification of the 16S rRNA genes from Mycoplasma bovis and Mycoplasma agalactiae by PCR

Mycoplasma bovis and Mycoplasma agalactiae are two very closely related species which cause mastitis in cows and goats, respectively. M. bovis can also cause arthritis and respiratory disease in cattle. It has recently been shown that the 16S rRNA sequences differ only in 8 nucleotide positions between the two species [J.G. Mattsson, B. Guss and K.-E. Johansson (1994) FEMS Microbiol. Lett., 115: 325-328]. These nucleotide differences are distributed over the molecule in such a way that it is difficult to design specific identification systems, based on PCR only, for M. bovis and M. agalactiae. Two different PCR systems based on 16S rRNA sequence data have, however, been designed for these two species. The forward primers were identical in the two systems and complementary to a segment of the evolutionarily variable region V2. The reverse primers were complementary to the variable region V6, in which there are two nucleotide differences between M. bovis and M. agalactiae. The size of the PCR products, generated with these primers, was 360 bp. Cross-amplification was obtained with the two species in the heterologous PCR systems, but with approximately a 100-fold lower efficiency. Cross-amplification was not obtained with any other bovine or caprine mycoplasma except for Mycoplasma sp. strain A1343 of the caprine group 7. The detection limit of the PCR system for M. bovis with a reference culture was 4 x 10(2) CFU/ml and of the PCR system for M. agalactiae 2 x 10(2) CFU/ml. The M. bovis-PCR system was used to analyze nasal samples of calves from a herd where an outbreak of pneumonia had occured and it proved possible to detect M. bovis in these samples.

Development of two PCR assays for the identification of mycoplasmas causing contagious agalactia

A new detection test for the mycoplasmas causing contagious agalactia, Mycoplasma agalactiae, M. capricolum subsp. capricolum and M. mycoides subsp. mycoides L. C., was developed. It was based on two polymerase chain reaction assays: the Ma-PCR for the detection of M. agalactiae and the MYC-PCR for the 'mycoides cluster' thus including M. capricolum subsp. capricolum and M. mycoides subsp. mycoides L. C. An M. agalactiae strain was identified by a 933-bp Ma-PCR product and no amplification with the MYC-PCR. In contrast, a 460-bp MYC-PCR product and a negative or a 350-bp Ma-PCR product characterized a 'mycoides cluster' strain. M. capricolum subsp. capricolum and M. mycoides subsp. mycoides L. C. were identified by their species-specific AseI pattern of the 460-bp MYC-PCR product.

Application of an arbitrarily-primed polymerase chain reaction to mycoplasma identification and typing within the Mycoplasma mycoides cluster

An arbitrarily-primed polymerase chain reaction (AP-PCR) was developed using a primer pair, Mlip1 and Mlip4, for members of the Mycoplasma mycoides cluster, a group containing important pathogens of small and large ruminants. Parameters that influence the reproducibility of this assay were optimized: magnesium, primer and template concentrations, and pH. AP-PCR fingerprinting, carried out on a number of strains of each of the six species or subspecies belonging to the mycoides cluster, allowed the typing of strains within each group. The AP-PCR assay showed that the cluster can be divided into two groups: (i) high and (ii) no genomic polymorphism variation. In addition, specific polymorphic bands for members of species or subspecies included in this cluster were amplified by this AP-PCR method, thus allowing their identification.

Cytokines induced in vitro by Mycoplasma mycoides ssp. mycoides, large colony type

Septicemic disease in goats and sheep caused by the large colony type of Mycoplasma mycoides ssp. mycoides has clinical and pathological features in common with septic endotoxemia. We studied the ability of the mycoplasma to induce mediators of biological responses to endotoxin, such as TNF alpha, IL-1 alpha, IL-6 and nitric oxide. Heat-killed suspensions of mycoplasmas in a concentration of 25 micrograms protein ml-1 induced all mediators in macrophages from peritoneal cavity and bone marrow of both C3H/HeN (LPS responsive) and C3H/HeJ (LPS low-responsive) mice. Lipopolysaccharide (LPS) in a concentration of 100 ng ml-1 induced the mediators in C3H/HeN derived macrophages, only. Simultaneous stimulation of macrophages with interferon-gamma enhanced the secretion of nitric oxide (measured as nitrite) but not the cytokines. We conclude that heat-killed Mycoplasma mycoides ssp. mycoides, large colony type, has cytokine inductive activity similar to bacterial endotoxin, but with an induction mechanism different from LPS.

Mycoplasma infection in a commercial goat dairy caused by Mycoplasma agalactiae and Mycoplasma mycoides subsp. mycoides (caprine biotype)

A commercial dairy goat herd of 600 animals experienced sudden onset of arthritis/polyarthritis, clinical mastitis, and sudden death in does. The offending infectious agents were Mycoplasma agalactiae and M. mycoides subsp. mycoides (caprine biotype). The disease syndrome began approximately 4 weeks following the 1) introduction into the herd of a lactating doe with no apparent clinical signs and 2) a breakdown of proper hygienic conditions in the milking parlor. Over a period of 3 weeks, 90 does (15%) either died or were culled because of arthritis/polyarthritis and mastitis. A management decision resulted in only the does affected with M. mycoides subsp. mycoides being submitted for necropsy; those affected with M. agalactiae, which were in a different "string," were not submitted for evaluation. Gross necropsy of the does affected with M. mycoides subsp. mycoides showed purulent discharges from the udders, enlarged supramammary lymph nodes, enlarged and firm spleens, and swollen livers. Microscopic findings were characterized by a loss of vascular integrity and diffuse fluid leakage in multiple organs. Antibiotic therapy with tylosin was attempted but was not successful. The outbreak was terminated following the removal or segregation of affected does and implementation of hygienic conditions in the milking parlor.

Characterization of the 16S rRNA genes from Mycoplasma sp. strain F38 and development of an identification system based on PCR

Mycoplasma sp. (strain F38) is the causative agent of contagious caprine pleuropneumonia, which is a goat disease of great global concern. Strain F38 belongs to the so-called "Mycoplasma mycoides cluster," and the members of this cluster have many biochemical and serological properties in common, which makes it difficult to differentiate between them by conventional methods. Their phylogenetic interrelationship are thus uncertain. The 16S rRNA gene of the rrnB operon from strain F38 was cloned and sequenced. The sequence was compared with the 16S rRNA sequences of related mycoplasmas, and phylogenetic trees were constructed by parsimony analysis. A three-way ambiguity among strain F38, Mycoplasma capricolum, and Mycoplasma sp. strain PG50 was observed in the trees. This observation is in agreement with a recent proposal to reclassify strain F38 and M. capricolum. A primer set was designed for in vitro amplification by PCR of a fragment of the 16S rRNA genes from the M. mycoides cluster. The amplimers of strain F38 could be distinguished easily from the corresponding amplimers from other members of the M. mycoides cluster by restriction enzyme analysis with PstI. This observation was utilized to design an identification system for strain F38. Part of the 16S rRNA gene of the rrnA operon from strain F38 was also cloned, and several sequence differences between the two rRNA operons were discovered, revealing microheterogeneity between the two 16S rRNA genes of this organism.

Analysis of membrane proteins of Mycoplasma capricolum strains by SDS-PAGE and immunoblotting

Sixteen moroccan and five other Mycoplasma (M.) capricolum strains were characterized by SDS-PAGE as well as by the immunobinding assay and immunoblotting, using antisera against M. capricolum California Kid (CK) and M. mycoides YG. There was a strong reaction of all 21 strains with antiserum against M. capricolum CK and of 18 strains with antiserum against M. mycoides YG in the immunobinding assay, confirming the cross-reactivity between these two species observed earlier. A marked heterogeneity among the M. capricolum strains appeared in SDS-PAGE and in immunoblotting, characterized by different protein patterns and different strengths of identical protein bands. All M. capricolum strains investigated revealed, however, at least three strong protein bands with mol. weights of about 30, 42 and 52 KD reacting in immunoblotting with antiserum against M. capricolum CK but not with antiserum against M. mycoides YG. These proteins may represent antigens suitable for the identification and differentiation of M. capricolum strains.